AW: Dirty bombs- Cs-137 movement into soil question

["Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>]

-----Ursprüngliche Nachricht-----

Von: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von BERNARD L COHEN

Gesendet: Montag, 03. März 2003 16:05

An: Stewart Farber

Cc: Jim Hardeman; Radsafe

Betreff: Re: Dirty bombs- Cs-137 movement into soil question





>

> For fresh fallout, sitting on the soil surface one uses a specified factor

of

> flux to areal concentration. As time goes on Cs "moves" into the soil and

the

> flux for any average areal concentration would go down. However, Cs does

not

> reach a depth where it is difficult to measure by field gamma

spectroscopy,

> although on a sandy surface [with little if any organic content] with lots

of

> rain over many years, Cs might penetrate to a much greater depth.



	--Are the depths involved sufficient to give appreciable

shielding for health protection purposes? How effective would it be to

plow the surface under to some depth? In ion exchange columns, there are

many ways to desorb the adsorbed materials; would that be effective for

washing the Cs deeper into the soil? Of course, removing the soil surface

would not be a very expensive approach if it nothing else worked.



------------------------------

It is not clear to me, whether you refer to a nuclear accident with very

widespread contamination or to a "dirty bomb". But since a dirty bomb would

not be exploded on arable land, I rather assume that you refer to a nuclear

accident.

After the Chernobyl accident there were some ideas in Austria to deep-plough

the soil to move the Cs-137 to deeper layers. It was not done, because this

deep-ploughing would destroy the soil, so that hardly anything would grow on

it any more. Being a chemist I do not know of any chelating agents which

would selectively chelate Cs-137 and wash it into deeper layers. Of course

there is the possibility to desorb Cs-137 with agents like lactic acid,

EDTA, acetic acid or similar agents - but then you can forget about growing

any crops on that soil. After the Chernobyl accident some "green" groups

claimed, that the top soil should be removed from Austrian soil and that the

removed soil should be stored at our nuclear research center. I do not

remember the exact numbers, but you can easily calculate, what amount of

soil in cubic-kilometers would have piled up to remove about 30 cm deep soil

in an area of a few tens of thousands of square kilometers of arable land in

Austria.



Sorry to say, but your proposed solution of handling such a contamination is

far away from anything reasonable and acceptable. We have to work nowadays

together with all kind of other sciences - agriculture, chemists,

ecologists - in order to solve our problems.



Best regards,



Franz





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